Browse Publications Technical Papers 2016-01-0995
2016-04-05

The Effect of Diesel Exhaust Fluid Dosing on Tailpipe Particle Number Emissions 2016-01-0995

Introduction of modern diesel aftertreatment, primarily selective catalytic reduction (SCR) designed to reduced NOx, has increased the presence of urea decomposition byproducts, mainly ammonia, in the aftertreatment system. This increase in ammonia has been shown to lead to particle formation in the aftertreatment system. In this study, a state of the art diesel exhaust fluid (DEF)-SCR system was investigated in order to determine the influence of DEF dosing on solid particle count. Post diesel particulate filter (DPF) particle count (> 23 nm) is shown to increase by over 400% during the World Harmonized Transient Cycle (WHTC) due to DEF dosing. This increase in tailpipe particle count warranted a detailed parametric study of DEF dosing parameters effect on tailpipe particle count. Global ammonia to NOx ratio, DEF droplet residence time, and SCR catalyst inlet temperature were found to be significant factors in post-DPF DEF based particle formation. Thermogravimetric analysis (TGA) of ammonia salt particles and urea decomposition byproducts indicate significant chance of measurement using the Particle Measurement Programme (PMP) Particle Number (PN) method. These DEF based particles were not intended to be addressed by the PMP PN methodology, but are found to be over 80% of PN post DPF.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X